Southern California -- this just in

6 of 7 Marines killed in helicopter crash were from Camp Pendleton

Six of the seven Marines killed in a midair collision of two attack helicopters near Yuma, Ariz., were from Camp Pendleton and the seventh was from the base at Yuma, the Marine Corps said Thursday.

The collision between an AH-1W Super Cobra and a UH-1Y Super Huey occurred about 8 p.m. Wednesday in a remote area just west of the Yuma Training Range Complex. Both helicopters were from Camp Pendleton.

The area is used for training, in part because it mirrors the rough, irregular terrain and the hot, dry weather that helicopter crews will encounter in Afghanistan. Attack helicopter crews train in firing weapons and working in tandem, often at low altitudes.

"We're always training to deploy," said 1st Lt. Maureen Dooley, a spokeswoman for the 3rd Marine Aircraft Wing based at Miramar Marine Corps Air Station in San Diego.

Although the exact site has not been pinpointed, the crash is believed to have occurred on the California side of the Yuma range, near the Chocolate Mountains, a Navy-Marine Corps firing range for aircraft.

The names of the dead, and the name of their squadron, will not be released for at least 24 hours until families are notified, which is standard Marine policy.

The Cobra is the backbone of the Marine attack helicopter fleet, with a crew of two: a pilot and a co-pilot/gunner. It carries a "Gatling-style" cannon and several varieties of rockets and missiles.

The Huey is a twin-engine medium-size utility helicopter, with a crew of one or two pilots, a crew chief and others as the mission requires. It carries machine guns and rockets, among other armaments.

Photo: Undated image of an AH-1W helicopter, the type involved in a collision Wednesday near Yuma, Ariz., during night training exercises. The crash involved an AH-1W and a UH-1Y helicopter. Credit: U.S. Marines.